In the coming year we will increase the sensitivity of our DNA renaturation kinetic analysis in looking for PS8 phage DNA in crown gall tumors. We should, by increasing the specific activity of the P32 phage DNA, to be able to detect less than 1 phage genome per diploid plant cell. This will alllow us to settle the biological issue of whether any phage DNA is in tumor cells. In addition, we will attempt to isolate plasmid DNA from tumorigenic strains of Agrobacterium as reported by Schell and his collaborators. Labeled plasmid DNA will be used in DNA renaturation kinetic analysis with unlabeled tumor DNA to look for plasmid DNA sequences in tumors. We will attempt to determine whether A. tumefaciens strain C58, which loses elevated temperature, concomitantly loses a plasmid DNA.